Electric-arc lamp



(No Model.) v

E- THOMSON. ELEOTRIO ARC LAMP.

No. 508,656. Patented Nov. 14, 1893.

Flill numms'h In! lllllilllillllll l l|ll% UNITED STATES PATENT OFFICE.

ELlI-lU THOMSON, OF SWAMPSCOTT, MAssACHUsETTs, ASSIGNOR TO THETHOMSON-HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

ELECTRI -ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 508,656, dated November14, 1893.

Application filed February 4. 1892. Serial No. 4203M. (N model.)

nected in multiple between constant potential mains from burning orinjury due to excessive current caused by an abnormal arc. The inventionconsists in certain mechanism whereby the descent of the carbon or thefeeding action of the carbon to a predetermined point, as when thecarbons are fully consumed operates a switch which opens the circuit ofthe feeding magnet.

In the accompanying drawings Figure l is an elevation of a portion of anarc lamp embodying my invention, with circuit connections. Figs. 2, 3,4, 5, and 6 show modifications. Fig. 7 is a detail of the feedingactuator.

The feeding magnet K is in derived circuit around the are E, E as shownin Fig. 1, said circuit being completed through a switch W which duringthe normal operation of the lamp is closed; The lamp may be a ribbonfeed lamp in which a ribbon V suspends or holds up the upper carbon andits holder H and guiding frame, said ribbon going around a drum D whichis gradually rotated by the action of an endless screw mechanism shownat S, said endless screw mechanism being actuated by the derived circuitmagnet or feeding magnet on the presence of a slight increase from thenormal electro motive force of the are. For this purpose the magnet Koperates a pawl k and ratchet wheel M, Fig. 7 and this wheel actuatesthe worm and worm wheel feed, as shown in Fig. 1. The feeding mechanismis no part of the present invention as it is disclosed in my Patent No.458,025 of August 18, 1891. The switch W is held closed during thenormal feeding of the carbon, by engagement of the periphery of the drumD with the switch lever L. When, however, the carbon holder hasdescended to its lowest limit, a depression in the drum periphery comesopposite the engaging tooth on the switch lever and said tooth dropsinto the depression, opening the switch W and the circuit of the shuntmagnet.

Fig. 2 is a diagram, showing a modified but typical arrangement, K beingthe feeding magnet and D the drum upon which the ribbon V Fig. 1 iswound and which rotates as the ribbon V and upper carbon are fed duringthe action of the lamp. An ordinary gearing and detent pawl areindicated as constituting the feeding mechanism. The small depression earriving opposite the projection on the lever L will allow said lever tomove under the action of its elasticity or spring to open the switch WVand at all other points the drum will hold said lever down and keep theswitch W closed. This action of opening the switch is sudden as theprojection is made with an edge which slips quickly into the depression,also made with a sharp edge. In order to enable the projection to freelypass out of the depression at e on the restoration of the parts as bythe rotation of the drum D backward during resetting of the carbon afterconsumption, said projection is made in the form of a small hinged pawlP with a spring, as shown, which enables it to be set over or to pass bythe edge of the drum and slip upon the periphery of the drum out of thedepression c. This is a minor detail and the result may be accomplishedin other ways.

Fig. 3 shows the switchW operated by the depression e in an ordinarycarbon rod marked V, the lever L which controls the switch having aprojection which drops into the depression at e on the rod V arriving ata predetermined position of descent.

In Figs. 4, 5, and 6 the switch opening lever pressed upward by thespring Z has on it a projection at l which as the drum D rotates duringthe descent of the carbon and the downward motion of the ribbon Vfinally slips into the cavity or depression e in the drum, the part Zbeing shown as just ready to drop into the depression, or just passingover the edge thereof, at which time the switch WV is opened and remainsopen so long as the parts remain in position. The downward tendency ofthe ribbon V acts against a coiled spring ltending to rotate the drum inthe opposite direction. The tendency of the ribbon V to rotate the drumis so far in excess owing to the weight of the carbon holder and thecarbon itself and its guides that the descent of 5 Vwinds up or coils upthe spring T. On the insertion of carbons by raising the holder II thespring '1" reasserts itself and turns the drum D so as to keep theribbon Vtense,and to prevent the projection on the leverL from tostopping such backward movement by engaging with the sharp edge ofdepression e, said depression has an offset inclined portion U and thelever L is pressed slightly laterally as indicated in the figure by thedotted lines and is then forced out of the depression (2 on the inclinedsurface. Thus the drum D may rotate backward so as to coil up the ribbonV without hinderance from the pin Zwhen dropped into the depression 6.

While I have indicated the switch as breaking only the circuit of theshunt magnet, it may be used to break the circuit of the entire lamp byarranging the connectors as indicated in dotted lines X Yin Fig. 3, theconnectors a, 0, being inthat case omitted.

What I claim as new, and desire to secure by Letters Patent, is-

1. The combination with the rotary support for the carbon holder, havinga depression, of 0 a circuit controller engaging with such support andmeans for impelling the engaging part of such controller into saiddepression.

2. In an arc lamp, the combination with the carbon holder, of a rotarysupport therefor having a depression, containing on one side an inclinedsurface, and a circuit controller having a projection engaging with saiddepression, substantially as described.

3. In an arc lamp, the combination with the carbon holder, of a rotarysupport therefor having a depression containing an inclined surfaceleading off to one side, and a circuit controller having a projectionengaging with said depression, substantially as described.

4. In an arc lamp, the combination with the carbon holder, of a springactuated drum, a ribbon wound on the drum and attached to the carbonholder, and a circuit closer adapted to be operated by said drum,substantially as described.

5. In an arc lamp, the combination with the carbon holder, of a rotarysupport therefor, and a circuit controller adapted to be operated bysaid rotary support, substantially as described.

ELIHU THOMSON.

Witnesses:

JOHN W. GIBBONEY, BENJAMIN B. HULL.

